This handheld mass spectrometer could make surgeries to remove cancerous tissue quicker and more accurate

“Did you get it all?” is a question many cancer patients ask when waking from surgery.

Unfortunately, cancer surgeons rarely know for sure. Surgeons will try to get “clean margins,” removing enough tissue around a tumor to ensure they’ve cut out any microscopic malignancies. But it’s an inexact procedure, and often results in healthy tissue being removed unnecessarily.

Now, researchers at the University of Texas at Austin and the Baylor College of Medicine have developed a device that could test tissue for cancer right in the operating room, leaving no question whether it should be removed or not.

The device is a pen-sized mass spectrometry device its developers are calling MasSpec Pen. The pen releases a droplet of water onto a tissue’s surface. The droplet attracts biomolecules from the tissue, and is then drawn back into the pen. The pen does a quick molecular analysis to determine whether the particles are cancerous or not. Within a few seconds, the surgeons know if they should remove the tissue.

“[With MasSpec Pen] we’re able to test tissue without taking tissue out,” says James Suliburk, a professor of surgery at Baylor who helped develop the device. “Right now, anything we want to test, we have to cut out. And we don’t want to cut out normal tissue. This allows us to be much more precise.”

The research team, led by UT chemistry professor Livia Schiavinato Eberlin, tested the MasSpec pen on tissues removed from 253 cancer patients. The pen gave a diagnosis in about 10 seconds, with more than 96 percent accuracy. It was also able to detect subtle changes in tissues in the margins between normal and cancerous tissues.

These results compare favorably with the standard technique for testing tissues during surgery. This technique, called a frozen section analysis, involves surgeons cutting out tissues and sending them to the pathology lab, where a pathologist looks at them under the microscope. This can take 30 minutes or more, during which time patients are lying on the operating table under anesthesia. While frozen section analysis is usually accurate, for some types of cancers it can give inconclusive or even false negative results.

The MasSpec Pen works by analyzing metabolites, small molecules produced by all cells. Cancers produce specific metabolites, which can be identified by the pen’s mass spectrometer. When the device is done reading, the words “cancer” or “normal” appear on a computer screen. For some types of cancers, the device will also tell surgeons the specific subtype.

So far MasSpec Pen has only been tested on tissues in the laboratory. The team will begin human trials in 2018.

“We still haven’t proved that it’s going to work inside the operating room,” Suliburk says.

Getting a new device into the sterile field of the operating room is a logistic challenge: where does it go relative to other pieces of equipment? Where do you put the power source? How can it be cleaned to ensure it doesn’t introduce germs? And then, of course, there’s the bigger question: will it work the same way in live patients as it does with tissue in a lab?

With all the testing to be done, even with optimal results, it will still be at least several more years before MasSpec Pen could be ready for use in a real operating room. The researchers and UT Austin have applied for patents for the technology.

But if it proves successful in trials, it could be a “game-changer,” Suliburk says.

“We’re changing up something that has been done the same way in surgery for half a century,” he says. “I think probably Harvey Cushing’s invention of the electrocautery almost 100 years ago is the last thing that was as revolutionary as this could be.”